| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ablsimpnosubgd.1 |  |-  B = ( Base ` G ) | 
						
							| 2 |  | ablsimpnosubgd.2 |  |-  .0. = ( 0g ` G ) | 
						
							| 3 |  | ablsimpnosubgd.3 |  |-  ( ph -> G e. Abel ) | 
						
							| 4 |  | ablsimpnosubgd.4 |  |-  ( ph -> G e. SimpGrp ) | 
						
							| 5 |  | ablsimpnosubgd.5 |  |-  ( ph -> S e. ( SubGrp ` G ) ) | 
						
							| 6 |  | ablsimpnosubgd.6 |  |-  ( ph -> A e. S ) | 
						
							| 7 |  | ablsimpnosubgd.7 |  |-  ( ph -> -. A = .0. ) | 
						
							| 8 |  | elsni |  |-  ( A e. { .0. } -> A = .0. ) | 
						
							| 9 | 7 8 | nsyl |  |-  ( ph -> -. A e. { .0. } ) | 
						
							| 10 |  | eleq2 |  |-  ( S = { .0. } -> ( A e. S <-> A e. { .0. } ) ) | 
						
							| 11 | 6 10 | syl5ibcom |  |-  ( ph -> ( S = { .0. } -> A e. { .0. } ) ) | 
						
							| 12 | 9 11 | mtod |  |-  ( ph -> -. S = { .0. } ) | 
						
							| 13 | 12 | pm2.21d |  |-  ( ph -> ( S = { .0. } -> S = B ) ) | 
						
							| 14 |  | idd |  |-  ( ph -> ( S = B -> S = B ) ) | 
						
							| 15 |  | ablnsg |  |-  ( G e. Abel -> ( NrmSGrp ` G ) = ( SubGrp ` G ) ) | 
						
							| 16 | 15 | eqcomd |  |-  ( G e. Abel -> ( SubGrp ` G ) = ( NrmSGrp ` G ) ) | 
						
							| 17 | 3 16 | syl |  |-  ( ph -> ( SubGrp ` G ) = ( NrmSGrp ` G ) ) | 
						
							| 18 | 5 17 | eleqtrd |  |-  ( ph -> S e. ( NrmSGrp ` G ) ) | 
						
							| 19 | 1 2 4 18 | simpgnsgeqd |  |-  ( ph -> ( S = { .0. } \/ S = B ) ) | 
						
							| 20 | 13 14 19 | mpjaod |  |-  ( ph -> S = B ) |